Get the bodies, footers working in the c-api

rust-ffi-demo/.gitignore

@@ -0,0 +1,2 @@
+demo
+demo.h

rust-ffi-demo/Makefile

@@ -0,0 +1,9 @@
+LDFLAGS := -L../src/rust-base/target/debug -lstorybook -Wl,--gc-sections -lpthread -ldl
+.PHONY: all clean
+all: demo
+demo: demo.h demo.c
+	$(CC) -g $^ $(LDFLAGS) -o $@
+demo.h:
+	cbindgen -c ../src/rust-base/cbindgen.toml --crate storybook --lang c -o demo.h ../src/rust-base
+clean:
+	rm -f demo demo.h

rust-ffi-demo/demo.c

@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdint.h>
+
+#include "demo.h"
+
+const char* story = "START\n"
+  "One day, Dane took a really big shit!\n"
+  "GOTO DIALOG\n"
+	"DIALOG\n"
+	"\"Wow, that was a really big shit!\"\n"
+	"1) Die [DIE]\n"
+	"2) Don't die <Strength 100+> [DONT_DIE] (-1 Honor)\n"
+	"DONT_DIE\n"
+	"But he died anyways.\n"
+	"GOTO DIE\n"
+  "DIE\n"
+  "Then he died. Fuck you, Dane!\n"
+  "THE END\n";
+
+int main() {
+  Book *book = storybook_make_book(story);
+
+  while(!storybook_is_ended(book)) {
+    char* s = storybook_get_body(book);
+    printf("%s\n", s);
+    storybook_free_string(s);
+
+    enum footer footer = storybook_get_footer(book);
+    switch (footer) {
+    case (FOOTER_ENDING):
+      printf("The End\n");
+      storybook_advance_nooption(book);
+      break;
+    case (FOOTER_GOTO):
+      storybook_advance_nooption(book);
+      break;
+    case (FOOTER_CHOICES):
+	    uint32_t option;
+	    printf("Make a choice: ");
+	    scanf("%d", &option);
+	    storybook_advance_option(book, option);
+    }
+  }
+  
+  storybook_free_book(book);
+  return 0;
+}

src/rust-base/Cargo.toml

@@ -3,8 +3,12 @@ name = "storybook"
 version = "0.1.0"
 edition = "2021"
 
+[lib]
+crate-type = ["staticlib"]
+
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+
 [dependencies]
 
 peg = "0.8.0"

src/rust-base/cbindgen.toml

@@ -0,0 +1,8 @@
+language = "C"
+
+[export.rename]
+
+"FooterType" = "footer"
+
+[enum]
+rename_variants = "QualifiedScreamingSnakeCase"

src/rust-base/my_header.h

@@ -1,19 +0,0 @@
-#include <cstdarg>
-#include <cstdint>
-#include <cstdlib>
-#include <ostream>
-#include <new>
-
-struct Page;
-
-template<typename T = void, typename E = void>
-struct Result;
-
-template<typename T = void>
-struct Vec;
-
-extern "C" {
-
-Result<Vec<Page>, ParseError<LineCol>> parse_story(const str *string);
-
-} // extern "C"

src/rust-base/src/lib.rs

@@ -1,3 +1,7 @@
+// Parsing
+
+use std::collections::HashMap;
+
 #[derive(Debug, PartialEq)]
 pub struct Page {
     id: String,
@@ -9,7 +13,7 @@ pub struct Page {
 pub enum Footer {
     Ending,
     Goto(String),
-    Choices(Vec<Choice>)
+    Choices(HashMap<u32, Choice>),
 }
 
 #[derive(Debug, PartialEq)]
@@ -56,7 +60,7 @@ peg::parser! {
         rule footer() -> Footer
             = "THE END" __ { Footer::Ending } /
               "GOTO" _ i:id() __ { Footer::Goto(i) } /
-              c:choice()+ { Footer::Choices(c) }
+              c:choice()+ { Footer::Choices(c.into_iter().map(|x| (x.option, x)).collect()) }
         rule choice() -> Choice
             = o:$(['0'..='9']+) ")" _ f:$((!redirect() [_])+) r:redirect() __ {
                 let (redirect, stat_change, stat_check) = r;
@@ -94,10 +98,154 @@ peg::parser! {
     }
 }
 
-pub fn parse_story(string: &str) -> Result<Vec<Page>,
-                                           peg::error::ParseError<
-                                                   peg::str::LineCol>> {
-    storybook_parser::story(string)
+pub struct Book {
+    pages: HashMap<String, Page>,
+    current_page: Option<String>
+}
+
+impl Book {
+    pub fn find (&mut self, id: &str) {
+        if self.pages.contains_key(id) {
+            self.current_page = Some(String::from(id));
+        } else {
+            self.current_page = None
+        }
+    }
+    pub fn is_ended(&self) -> bool {
+        self.current_page == None
+    }
+    pub fn get_current(&self) -> &Page {
+        match &self.current_page {
+            None => panic!("Asked for current page, but current page is None!"),
+            Some(s) => self.pages.get(s).unwrap(),
+        }
+    }
+    pub fn advance_nooption(&mut self) {
+        let footer = &self.get_current().footer;
+        match footer {
+            Footer::Ending => {self.current_page = None},
+            Footer::Goto(s) => {
+                let s = s.clone();
+                self.find(&s);
+            },
+            Footer::Choices(_) => panic!("No option for advance on choices page!"),
+        }
+    }
+    pub fn advance_option(&mut self, option: u32) {
+        let footer = &self.get_current().footer;
+        match footer {
+            Footer::Ending => panic!("Option provided for advance on ending page!"),
+            Footer::Goto(_) => panic!("Option provided for advance on goto page!"),
+            Footer::Choices(choices) => {
+                // TODO ban choices with failing stat checks
+                // TODO update stats based on stat changes
+                match choices.get(&option) {
+                    Some(choice) => {
+                        let s = choice.redirect.clone();
+                        self.find(&s);
+                    }
+                    None => panic!("Option not a valid choice for page!"),
+                }
+            }
+        }
+    }
+}
+
+impl From<Vec<Page>> for Book {
+    fn from(v: Vec<Page>) -> Book {
+        let it = v.into_iter().map(|p| (p.id.clone(), p));
+        let pages = HashMap::from_iter(it);
+        let mut book = Book {
+            pages,
+            current_page: None,
+        };
+
+        book.find("START");
+
+        book
+    }
+}
+
+// C API
+
+use std::ffi::CStr;
+use std::ffi::CString;
+use std::os::raw::c_char;
+
+#[no_mangle]
+pub extern fn storybook_make_book(string: *const c_char) -> *mut Book {
+    let string = unsafe {
+        CStr::from_ptr(string)
+    };
+    let string = string.to_str().expect("Error, input string not valid UTF-8");
+    let pages = storybook_parser::story(string).expect("Error, input string could not be parsed");
+    let book = Book::from(pages);
+    let book = Box::from(book);
+    Box::into_raw(book)
+}
+
+#[no_mangle]
+pub extern fn storybook_free_book(book: *mut Book) {
+    unsafe {
+        Box::from_raw(book);
+    }
+}
+
+#[no_mangle]
+pub extern fn storybook_free_string(s: *mut c_char) {
+    unsafe {
+        drop(CString::from_raw(s));
+    }
+}
+
+fn get_book_from_ref<'a> (book: *mut Book) -> &'a mut Book {
+    let book = unsafe {
+        book.as_mut().expect("Invalid Book pointer")
+    };
+    book
+}
+
+#[no_mangle]
+pub extern fn storybook_get_body(book: *mut Book) -> *mut c_char {
+    let book = get_book_from_ref(book);
+    let body = book.get_current().body.clone();
+    let body = CString::new(body).expect("Body cannot be converted to CString");
+    body.into_raw()
+}
+
+#[repr(C)]
+pub enum FooterType {
+    Ending,
+    Goto,
+    Choices,
+}
+
+#[no_mangle]
+pub extern fn storybook_get_footer(book: *mut Book) -> FooterType {
+    let book = get_book_from_ref(book);
+    match book.get_current().footer {
+        Footer::Ending => FooterType::Ending,
+        Footer::Goto(_) => FooterType::Goto,
+        Footer::Choices(_) => FooterType::Choices,
+    }
+}
+
+#[no_mangle]
+pub extern fn storybook_is_ended(book: *mut Book) -> bool {
+    let book = get_book_from_ref(book);
+    book.is_ended()
+}
+
+#[no_mangle]
+pub extern fn storybook_advance_nooption(book: *mut Book) {
+    let book = get_book_from_ref(book);
+    book.advance_nooption();
+    
+}
+#[no_mangle]
+pub extern fn storybook_advance_option(book: *mut Book, option: u32) {
+    let book = get_book_from_ref(book);
+    book.advance_option(option);
 }
 
 #[cfg(test)]
@@ -128,7 +276,7 @@ THE END
     #[test]
     fn storybook_parser_test() {
         assert_eq!(
-            parse_story(STORY),
+            storybook_parser::story(STORY),
             Ok(vec![
                 Page {
                     id: String::from("START"),
@@ -138,15 +286,15 @@ THE END
                 Page {
                     id: String::from("DIALOG"),
                     body: String::from("Dane: 'Wow, that was a really big shit!'"),
-                    footer: Footer::Choices(vec![
-                        Choice {
+                    footer: Footer::Choices(HashMap::from([
+                        (1, Choice {
                             option: 1,
                             flavor: String::from("Die"),
                             redirect: String::from("DIE"),
                             stat_check: None,
                             stat_change: None,
-                        },
-                        Choice {
+                        }),
+                        (2, Choice {
                             option: 2,
                             flavor: String::from("Don't die"),
                             redirect: String::from("DONTDIE"),
@@ -159,8 +307,8 @@ THE END
                                 value: 100,
                                 rel: '+',
                             })
-                        }
-                    ])
+                        }),
+                    ]))
                 },
                 Page {
                     id: String::from("DIE"),
@@ -170,4 +318,11 @@ THE END
             ])
         );
     }
+
+    #[test]
+    fn test_book_from_pages() {
+        let pages = storybook_parser::story(STORY).unwrap();
+        let book = Book::from(pages);
+        assert_eq!(book.current_page, Some(String::from("START")));
+    }
 }